Telephone-exchange system



H. W. uLRacl-n TELEPHONE EXCHANGE SYSTEM Fnesept. s, Ql

p magi f by .M5/ Aff/jf Patented Aug. 7, 1923.

UNITED sTATas tassen PATENT 4orf-islet.;

HORACE W. ULRICH, EAST ORANGE, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW NEW YORK.

Application led September 5, 1919.

T 0 all w from t may con-cem Be it known that I, HORACE WV. ULRICH, a citizen of the United States, residing at East Orange, 'in the county of Essex, State of New Jersey, have invented certain new and useful Improvements in Telephone-Exchange Systems, of which the following is` a tull,clear, concise, and exact description.

This invention. relates to telephone exchange systems, and more particularly to such systems in which connections between telephone lines terminating at manual and automatic exchanges are established by way of trunk circuits, over which automatic switches are controlled `from the manual exchange for effecting connections between the trunk circuits and telephone lines at the automatic exchange.

The object ot this invention is the production ot an improved system of this character by which the operators at a manual exchange may control over the trunk circuit the automatic switches provided at the automatic exchange, for establishingr connections between the trunk circuits and the telephone lines.

In accordance with the various features of this invention, an operators impulse sending device provided at the manual exchange and common to the link circuits thereof, is rendered individual to any one of the link circuits by the 'actuation of a switch individual thereto; means provided in an associated trunk circuit extending to the automatic exchange is responsive tothe actuation of the switch to interrupt the continuity of the trunk circuit, and means associated with the engagcdlink and trunk circuits is thereafter controlled by the impulse sending device tointermittently close the trunk circuit extending to the, automatic exchange for controlling the selecting mechanism thereat.

For a more complete understanding of this invention, reference should be had to the following description considered in connection with the accompanying drawing which illustrates one embodiment of the invention.

There is shown in `the drawing a telephone line A, terminating at a manual exchange, where it may be connected with lthe link circuit B in any suitable and well known manner. The calling end ot the link circuit B be connected with the trunk circuit C YORK, N. Y., A CORPORATION 0F TELEPHONE-EXCHANGE SYSTEM.

Serial No. 321.853.

extending from the manual to an automatic exchange, at which are provided' the usual the automatic exchange.y At the automatic exchange the trunk circuit is multipled to.'

to the jack terminals at a toll switchboard at which is located the link circu'itE, by

means of which connection may be estab-` lished with the trunk circuit and signals at the manual exchange controlled theretroin The apparatus shown to the lett of the ver' tical dotted line is located at the manualb exchange, while that shown to the right ot" the dotted line is located at the automaticv exchange. The nature of this invention is such that it is believed a clear understand! ing thereof will be obtained from a description of the operation of systems shown in the drawing and it will be 'so described.

The subscriber at the station on telephone line A having initiated a call and the answering end of the link circuit B having been associated therewith in any well known manner, the operator actuates listening key 5, connecting the operators telephone set in circuit so that the operator may converse with the calling subscriber and ascertain the number ot the linewith which connection is desired. Assuming that connection is desired with telephone line D which terminates at the automatic exchange, the operator inserts calling plug 6, ot the link cir cuit B, into jack 7 otk'the trunk circuit C. i

Relays 8 thereupon operates over a circuit from battery rthrough resistance 9, lower normal Contact ot sending device connect` ing key 10, sleeve contacts of the plug 6 and the jack 7 and the windings of relay 8 to ground. Relay 8 in operating opens its right-hand contact, disconnecting the energizing winding ot ring-up relay 11 from bridged relation with the talking conduct-ors of the trunk circuit C and closes its lefthand contact causing the energization of relays 12, 13 and 14. The first two relays, 12 and 13,` operate over a circuit from battery through the winding of relay 13, the right-hand winding of relay 12, and the left-hand contact of relay 8 to ground. Relay 12 in operating 'connects its low resistance lett-hand winding in parallelwith the high resistance right-hand winding` of relay 8, while theloperation ot relay 13 opens a,

contact in the circuit of relay 15 and a contact in circuit with relay 16, the former of which is connected with the tip talking conductor of the trunk circuit and the latter with the ring talking conductor thereof. The operative association of these relays 15 and 16 with the talking conductors is thereby interrupted. Relay 13 also vcauses the operation of busy signal 17 and bridges ringing response relay 18 across the talking con ductors of the trunk circuit. Relay 14 operates over a circuit from 'battery through the contact of relay 18, winding of relay 14, and the left-hand contact of relay 8 to ground. Relay 14 in operating establishes a yshor-t circuit for the right-hand winding of relay 12. This relay 12 thereupon releases its armature since, when it is in circuit with resistance 9 Vand its right-hand winding is short-circuited, and the normal contact yof listening key 5 is open, it does not receive sufficient current through its left-hand winding to hold its armature attracted. Condensers 28 and 29 connected in the talking ,conductors of the trunk circuit C serve to electrically divide these conductors into inner and outer sections, so that current from the battery in ythe link circuit will not flow ou-t to the au-tomatic exchange and current from the battery at the automatic exchange will not affect apparatus con-nected with the inner section of the talking conductors.

The operator after `connecting the link circuit B with the trunk circuit C may actuate the sending device connecting key 10, which interrupts the continuity of the tip talking conductor and sleeve conductor of the link circuit B, whereupon relays 8, 16 and 14 release their armatures, reconnecting relays 11, 15 and 16 with -the talking conductors. vThe closure of the lower lalternate contact of key 10 causes the operation of pilot relay 20 over a circuit from battery through resistance 9, lower alternate con tact of key 10, and the winding of pilot relay 20 to ground. A sending device pilot lamp 21 is thereupon lighted. The release of relay 13 causes the operation of relay 16 over a circuit from battery through the winding of supervisory relay 22, lower normal con tact of ringing key 23, ring contacts of the plug 6 and the ack 7, winding of relay 16, normal contact of relay 11, and right-hand normal contact of Vrelay -13 to ground. Bellay 16 in operating interrupts the continuity of the tip and ring talking conductors of the outer section ofthe trunk circuit and opens the original operating circuit of busy'signal 17, but before this operating circuit is opened a holding -path is established Vtherefor so that busy signal 17 Yisfinaintained op-A erated while relay 16 isenergiZed.

- "The closure of .the upper alternate con` tact ofkey `10 connects the operator-s -imfy pulse sending device 24 with the tip talking conductor of the engaged link and trunk circuits B and C, causing the energization of relay 15 over a circuit from Abattery throu,. rh the outer left-handV Contact of relay winding of relay 15, tip contacts-of the jack 7 and the .plug 6, upper alternate contact of'key 10 and the contact of sending device 24 to ground. `Relay 15 upon being energized closes its outer right-hand contact, causing the energization of impulse-responsive relay 25 over a circuit from battery through the left-hand winding of impulse-'responsive re lay 25, left-hand contact of cuto' relay 34, outer right-hand contact of relay 15, upper alternate contact of relay 16, right-hand contact of cutoff relay 34, and -the right hand winding of impulse-responsive relay 25 to ground. Relay 15 is thereafter deenergized upon each opening of the contact of sending device 124 and energized upon each closure of this contact, so thatimpulse-responsive relay 25 follows the operation `of the sending dev-ice 24 to control the usual motor magnets and other control Vapparatus governing the selector and connector switches at the automatic exchange.

After the requisite selecting impulses have been transmitted, due Ato the operation ofthe impulse sending device 24,-the switches 26 and 27 establish connection `between the trunk circuit C and the telephone line 1) r[he operator may, after 4the selecting impulses have been transmitted, firstv restore the connecting key 10 to its normal position and then restore listening key 5 to its nor-v mal position. Upon the restoration of key 10 to normal position, the impulse sending device 24 andthe pilot relay 20 are disconnected from the link circuit B and the-continuity of the tip talking land sleeve con-V ductors of the link circuit are reestablished. Upon the opening` of the alternate contacts of this key 10, relays 15 and 16 deenergize and release their armatures, andupon the closure of `the llower normal contact of the key, relay 8 operates causing` the operation of relays 12, 13 and 14. The operation of relay 14 short-circuits the right-hand winding of relay 12, causingthe deenergiza'tion of this relay 12 in the manner before describe-d. The restoration of the listening'key 5 to norixal position disconnects jthe -operators telephone set from the link circuit and connects supervisory lamp 30 and ree sistance 31 in parallel with `the resistance f9 and in circuit with the windings of relay S. The lamp 30 willnot be lightedwhile the right-hand winding of relay 6 is in circuit therewith. i i

The party at thestation'on telephone line D, in Iresponding to the operation of the call bell thereat(thef operation 4thereof being-caused in-Hany rWell known Ymanne-r) removes. the receiver from -the-switchhook Wherehy the parties at the stations on the telephone lines A and D may converse. At the conclusion ot the conversation the suhscribers restore the receivers to the switchhoolts and the operator at the manual eX- change, after observing the usual disconneet signal result-ing from the `restoration of the receiver to the svvitchhool on telephone` line A, disconnects the plug 6 from the jack 7, whereupon the apparatus ot the linl; and trunk circuits restoresto normal position.

Should the toll operator at the automatic exchange desire to establish connection with a telephone line terminating at the manual exchange, plug 35 of the link circuit E is inserted into jack 36 and ringing key 3'? is actuated and restored to normal position. Cutoff relay 34 operates upon connection of the link circuit E with the trunk circuit C to disconnect the impulse-responsive relay 25 from the trunk circuit, whereby the false operation of the automatic switch control apparatus is prevented. Relay 46 also opcrates, causing supervisory lamp 44 to be f lighted until the manual operator ansvers.

The actuation of this ringing key causes the energization ot' ring-up relay 11 over a circuit from a source of ringing current 38.,

lower alternate contact of ringing key 37, n l ring contacts o1' the plug 35 andthe gaclt 36, lower normal contact oit relay lturigvht-` hand contact of relay 8, left-.hand `Winding of relay 11, condenser 39, upper normal contact of relay 16, tip contacts et the lrack 36 and the plug 35, and the upper alternate contact ot ringing key 87 to ground. `Relayll upon being energized, loclrs up over a circuit Yfrom battery through its right-hand vrindH ing and righthand alternate contact, and the inner rightdiand contact ot vrelay 13 to ground. The closure of the left-hand contact of relay 11 causes lamp 40 to be lighted over a circuit :from battery through the letthand contact of relay 11, lett-hand normal Contact ot relay 15, and the 40 to ground. Relay 11 `in operating also opens a contact in circuit with relay 16.

l The operator the manual exchange upon observing the lighted condition ot the lamp 40, inserts plug 5 ofthe link circuit B into the jack'- 7 ofthe trunk circuit C. Relays 8, 12, 13 and 14 thereupon operate inthe manner before described. The operation ot relay 13 opens the locking circuit ot relay 11 which thereupon releases its armatures, ei;- tinguishing the lamp 40. rllhe operation oit relay 13 also causes the energiaation. ot supervisory relay 43 overa circuitfrom battery through the right-hand Winding ot relay 43, lower normal contact of ringing` le 37 rin@- contacts ot the nlug 35 and t in 7 J J jaclr 36, impedance coil 45, outer rlghtfhan 1l contact of rela f 13 ti contacts ot the iaclr 3,6 and the plug oo, the upper normal con tact ot ringing key 3T .and the `left-hand Winding of supervisory relay 43to ground. The .operationof supervisory relay 43, eX- tinguishes the supervisory lamp 44 indicating to `the toll operator that the manual op-` erator has answered. `The operation of re` lay 14 establishes a short circuit for the right-hand Winding of relay 12 but this re! lay 12 does not release its armature at this time, for listening key 5 is in its normal po-` sition` and the lamp 30 and resistance 31 are` connected in parallel with the resistance 9.v l

Therefore,y sufficient current traverses they lett-hand Winding of relay 12 tocause it to maintain its armature attracted. `This low resistance lett-hand Winding ot relay 12 is` connected vin parallel with the high resist-` ance right-hand Winding ot relay8 so `that the lamp 30 receives suliicientcurrentto'v cause it to belighted. 5 .f

The toll operator after-.restoring ringing; key 37 to .normal position and after noting that the supervisory lamp 44 has been eX- tinguished, may actuate listening ley 41 t connecting the toll operators telephone set with the talking conductors.` Likewise the operator at the manual exchange after inserting the plug 6 into the jack 7, may ac t-uate the listening key 5 .to connect the manual `operators telephone set with the talking conductors so that the two operators may converse. The opening ot the normal contact of listening'lrey 15 removes thelamp 30 and the resistance 81 from parallel relation with the resistancevQ, thereby increasing `the resistance in circuitr with the lefthand Winding of relay 19,. Suliicient cur-l rent does not flow through ,this Winding toy caust` the armature to he maintained' in attracted position so that this armature is released. Of course, the opening of the normal contact of listening key 5 extinguished the lamp 30. By means of the link circuit B, the operator at the manual'exchange may complete connection with the desired telephone line in the usual and Well known manner. After establishing such connection the respective listening keys of the operators may be restored to normal position. The restoration of the listening glrey 5 to normal position reconnects the lamp 30 andresistance 31in parallelwith the resistance 9; rlhe contactr of relay 12 is at this time open and the right-hand Winding thereof'is shortcircuited so that relay 1.2 is not reenergized, and since the lowresistance lett-hand Winding of relay 12 is not connected in parallel with the high resistance right-hand Windw -ing ot relay 8, the lamp rwill not he lighted. l y

Should the toll operator desire to recall the operator at themanual exchange, this may be done by actuating the ringing key 37 tor a short time. kDuring the time that this ringing key is actuated, relay 18 energizes over a circuit from thesource of ringing current 38,.:flowver alternate -:.contact of vringing key 37, rin-'g contacts of the .plug V85 and the .jack

36, condenser ec'viindinglof relay 18, outer` rightlhand 'contact-'ot relay 13 and outer `left-hand*contact olf relay 14 in parallel,

tip vcontacts ci the jack 186 andthe plug 35, and the upper alternate conta-ct of ringing kev 37 to ground. `During the energization `supervisory lamp 30, normal contactV of listening key 5, and the left-hand Wind-ing and contact of lrelay 12. The lei'tihand Wind-ing of relay 12 is lnow connected in parallel with the-right-hand Winding of -relay 8 vso that fthe lam-p30 lights. y

"The deenergiz'ation 'of relay 18 lupon the restoration of the `ringing key l37 `to normal position reestablishes the energizing circuit of slow-release relay 114, whereby the short circuit about the 'right-hand winding off irelay 12 is reestablished. Relay 1Q remains energized, however,I since When the lamp 30 is in circuit therewith, it receives suflicient current -to maintain its 'armature attracted. Relay 14 is vmade slow iin releasing so `that the short circuit about the right-hand Winding of relay 12 will not :be interrupted, due to anymerely momentary energiz'ation olf relay 18. The outer righthand contact of relay l13 Iand the outer left-hand contact-oi relay 14 are connected in 'parallel-so `that the bridge of the `talking conductors containing the relay 18 Will not be 'interrupted should the operator at `the Vmanual lexchange lmomentarily remove the plug from the ',ifack 7.

rllhe operator at the manual exchange upon observingthe lighted A"condition of the lam p 30 Vmayactuafte listening key'f to connect the telephone se't in circuit with the talking conductors so that this operator may lconverse With y'the toll operator, 'iv-hose telephone set is connected in circuit therewith upon the a'etuationo'if the listening key 41.' The opening o1 'the normal contact of listening key 5, extinguishesthe supervisory lamp "30 vand causes relay -1-2 to 4releaseits armature.

What is claimed is: 1. Ina telephone exchange system, in combination, a trunk circuit, an `operators link circuit connectedthereivith, an impulse sending device, fa key forconnecti-ng the-"impuls'eus'ending device `with the link circuit, means responsive to `the connection of "the ini-pulse sending device with the link circuit for'interrupting the continuity "of the talking conductors of the trunk circuit, anampulse responsive relay, and means responsive tothe actuation of the impulse sending device for intermittently bridging ythe talking conductors of the trunk Acircuit 'to control the impulse responsive relay.

f2. ln a telephone exchange system, in combination, a ytrunk circuit comprising va pair of talking conductors, a normally open bridge for `'the :talking conductors, an impulse responsive relay, an impulse sending device. a 4relay controlled over a portion of the talking conductors of the trunk circuit by the impulse sending device Jfor intermit tenltly closing the bridge to control the impulse responsive relay and means responsive to the disconnection of the impulse sending device 'from the trunk circuit for disconnesting the relay from the talking conclue tors. l

3. lIn a telephone exchange system, in combination, a trunk circuit comprising a pai-r of talking conductors, an operators link circuit connected With the trunk circuit, a normally open bridge for the talking conductors, an impulse responsive relay, an impulse sending device, a key for connecting the impulse sending device With the link circuit, and a relay controlled solely7 over a portion of one of the talking conductorsof lthe trunk circuit by the impulse sending device for intermittently closing the bridge to control the impulse `responsive 'relay.

4. In a telephone vexchange system, in

combination, a trunk circuit comprising a pair of talking conductors, an operators link circuit, an impulse sending device, an impulse responsive relay, means responsive to the connection of the link circuit with the trunk circuit for close-circuiting the talking conductors, a key for connecting the impulse sending device with the link circuit, and arelay controlled solely over a portion of one of the talking conductors voi the trunk circuit by the impulse sending device vfor intermittently interrupting the closed circuit including the talking conductors to control the impulse responsive relay.

5. In a telephone exchange system, in combination, a manual exchange, -an automatic exchange, a trunk circuit comprising a pair of talking conductors extending between said exchanges, an operators link cirllO cuit. means responsive to the connection of Y the link circuit with the trunk circuit for close-circuiting the talking conductors, an impulse sending device, a key for connecting the impulse sending device with the` link circuit, an impulse responsive relay at the automatic exchange. and a relay controlled solely over a portion of one of the talking 'conductors by the impulse sender for intermittently interrupting the closed circuit including the talking conductors to control-the impulse lresponsive relay.

' conductors.

i- 6. In a telephone exchange system, in combination1 a trunk circuit comprising a pair of talking conductora-a link circuit, a

'primary relay responsive to the connection of the link circuit `with the trunk circuit for close-circuiting the talking conductors, an impulse `sending device, an impulse responsive relay, a seconda-ry relay controlled over a portion ottone of the talking conductors by the impulsesending device for intermitltently intf-irrupting the closed circuit including the talking conductors to control the impulse responsive relay, and means responsive to thc disconnection `of the impulse sending device from the link circuit tor disconnectingthe secondary relay from the talking 7. ln a telephone exchange system, in combination, a trunk circuit comprising a `pair of talking conductors, a link circuit connected with thetrunk circuit,a primary relay energized over a portion of one of the means controlled by the primary and sec ondary relays for 'close-circuitiiig the talking conductors, an impulse responsive relay, and an impulse sending device connected with the link circuit and controlling the secondary relay for intermittently interrupting the closed circuit including the talking conductors to control the impulse responsive relay.

8. ln a telephone exchange system, in combination, a trunk circuit comprising a pair of talking conductors, inductive means connected in and electrically dividing the talking conductors into inner and outer sections, an operators link circuit, means responsive to the connection of the link circuit Witli the trunk circuit for close-circuiting the talking conductors or the outer section, an impulse sending device connected with the trunk circuit, an impulse responsive relay, and a relay controlled solely over a portion oic one of the talking conductors of the inner section by the impulse sending device for intermittently interrupting the closed circuit to control the impulse responsive relay.

9. In a telephone exchange system, in

combination, a trunk circuit comprising aV pair or talking conductors, inductive means connected in and electrically dividing the talking conductors into inner and outer sections, a link circuit, means responsive to the connection of the link circuit with the trunk circuit for close-circuiting the talking conductors of the outer section, an impulse sending device connected with the link circuit, an impulse responsive relay, a relay connected with one of the talking conductors of the inner section and controlled by the sending device for intermittently interrupting the closed circuit to control the impulse responsive relay, and means responsive to the disconnection of the impulse sending vdevice from the link circuit for interrupting the operative association of the relay with the talking conductor. y

l0. ln a telephone exchange system, in combination, a trunk circuit comprising apair of talking conductors, inductive means connected in and electrically dividing the talking conductors into inner and outer sections, a link circuit connected with the trunk circuit, a primary relay connectedl Withone otthe talking conductors ott the inner section, a secondary relay connected With the other 'talking conductor of the inner section and cooperating with the primary relay i to close-circuit the outer section, an impulse responsive relay, and an impulse sending device connected with the line circuit and controlling the secondary relay for intermittently interrupting the closed circuit to control the impulse responsive relay.

l1. In a telephone exchange system,in com-l bination, a trunk circuit comprising a pair of talking conductors, inductive means connected in and electrically dividing the talking conductors into inner and outer sections, a link circuit connected with the trunk circuit, a primary relay connected With one` of the talking conductors of the inner section, a secondary relay connected with the other talking conductor of the inner section and cooperating With the primary relay to close-circuit the outer section, an impulse responsive relay, an impulse sending device connected with the link circuit and controlling the secondary relay for intermittently interrupting the closed circuit to control the impulse responsive relay, and means responsive to the disconnection of the impulseA sending device from the link circuit for interrupting the operative association of the primary and secondary relays Wth the talking conductors.

l2. ln a telephone exchange system, in

and cooperating With the primary relay t0 close-circuit the outer section, an impulse responsive relay, an impulse sending device connected With the link circuit and controlling the secondary relay for intermittently interrupting the closed circuit to control the impulse responsive relay, and a relay energized over a circuit independent of the talking conductors in response to the disconnec- `sponsive relay, an impulse sendingdevice' tion of the impulse sending device from the link circuit for interrupt-mg the operative -association of the primary and secondary relays With the talking conductors I 13'. In atelephone exchange system, in

combination, a trunk circuit comprisinga pair of talking conductors, a. cordv circuit connected vvithk the trunk circuit, a relay vtinuity of the talking conductors, an impulse responsive relay, an impulse sending device connected with the cord circuit, and a relay connected with the other talk-ing' conductor and controlled by the impulse sending device for intermittently closecircuiting the talking conductors to control the impulse responsive relay.

14; In a telephone exchange system, in combination,l a trunk circuit comprising a pair of talking conductors, a link circuit connected with the trunk circuit, a relay operatingV over a portion of one of the talking conductors to interrupt the continuity of the tall'ing conductors, an impulse reconnected With the link circuit, a relay connected' withv the other talking conductor' and controlled by ther impulse sending: device for intermittently closefcircuiting. the talking conductors to control thev impulse responsive relay, andi a. rela-y responsive to the disconnect'ionl of the impulse sending device from the link circuit for interruptingthe operative association of the primary and secondary relays With the talking; conductors.

l5, In a telephone exchange system, in combination, a trunk circuit comprising a pair of talk-ing conductors, inductive means connected in. and electrically dividing the talking conductors into inner and outer sections, an impulse responsive relay, an impulse sending device,` a cord! circuit having a key therein for connecting the impulse sending device withv the trunk circuit, and a relay controlled' solely by the impulse sending device over one of the talkingconductors of the inner section for intermittently close-circuiting thev outerY section to control the impulse responsivey rel-ay;y

ln Witness whereof, I hereuntoy subscribeV my name this 2nd day of September A. De., 1919'.

HORACE W. ULRICH. 

